PM1

Carbon Braced Tweeter

You might imagine that any changes made in the frequency range above the limits of human hearing shouldn’t effect the sound we hear. And yet our experiments with diamond tweeters proved otherwise. By raising the break-up frequency far beyond the audible threshold of 20kHz, we created a tweeter that sounded far truer and more natural. With a break-up frequency of 30kHz, our aluminium dome tweeters already operate above the audible range. But inspired by diamond, we wanted to see if we could do even better for the PM1.

The result is an entirely new type of tweeter dome. By bracing the dome with a ring of filament-wound carbon fibre, we’ve raised the break-up frequency of aluminium to 40kHz. As a result, the PM1 features the sweetest-sounding aluminium dome tweeter we’ve yet produced.

Shaped for sound

When you look at the loudspeakers in the 800 Series Diamond range one thing immediately strikes you: the beautiful curvaceous head units. The PM1’s curved baffle echoes that shape, and for good reason: it smoothly disperses the sound around the speaker, helping to create a solid, three-dimensional image.Coupled with the placement of the tweeter on top of the cabinet, this significantly reduces the baffle area surrounding the drive units.

This produces an enhanced depth of soundstage, and a wider sweet spot.
The choice of materials helps to render the cabinet inert, which is vital on such a compact loudspeaker. The resulting performance is breathtaking in its ability to reproduce the audio signal, particularly when it comes to rendering the natural timbre of voices.

Anti-Resonance Plug

Where we lead, others eventually follow. It was back in 1974 that Bowers & Wilkins first discovered Kevlar’s unique ability to absorb the standing waves that can cause resonance in other midrange cone materials. Nowadays, you’ll see Kevlar® cones in many rival high-end speakers. But even as others adopt our technologies, we continue to innovate. And we see no reason to stop today.

For the PM1, we’ve enhanced the resonance-absorbing properties of Kevlar still further with a unique, entirely new feature: the anti-resonance plug. Constructed from polymer foam, the mushroom-shaped device soaks up resonance like a sponge while also reducing cone break-up, creating unparalled clarity and detail in the midrange. Kevlar just got better. And the bar for other speakers just got raised even higher.

Flowport

If you want to generate a big sound from a small speaker you’re going to need a decent set of lungs. The PM1 has the best breathing apparatus in the business, thanks to a special piece of proprietary Bowers & Wilkins technology we call Flowport™. Flowport helps the PM1 compensate its relative lack of internal space by regulating airflow in and out of the speaker. And it does so in a way that minimises the sound distortion that can mar the performance of other speakers.

Just like a golf ball, the dimples covering the exterior of the vent create little eddies of air, cushioning airflow across the surface of the Flowport and reducing the turbulence that produces unwanted “chuffing” noises. With Flowport, you get smooth air in, and nothing but pure, full-bodied sound out.

More to explore

Innovation

Every discovery our scientists make influences how loudspeakers all over the world are designed and built.